One problem with operation of brushless direct current motors of the type that are commonly used to provide electronic equipment cooling is that the leakage inductance between the motor windings may produce significant leakage inductance voltage spikes on the drive transistors. Also overlapping commutation results in current spikes on the motor power source.
Unless controlled or suppressed, the leakage inductance voltage and overlapping commutation current spikes may produce significant electromagnetic interference effects in associated electronic circuitry. In the past, suppression circuitry has been utilized to minimize the effect of leakage inductance spikes.
A significant disadvantage to the prior approach of suppression is that the suppression utilizes capacitors, either bypass capacitors or cross coupling capacitors across the motor windings. This is a disadvantage because the use of any component that can not be integrated onto an integrated circuit leads to extra cost and physical space requirements.
It is therefore desirable to provide a motor controller circuit that reduces the required capacitance to suppress leakage inductance and overlapping commutation spikes.